When contamination is detected by any monitor, what is the first action you should take?

• A. Stop
• B. Proceed with caution
• C. Ignore the detection
• D. Notify a supervisor later

Answer: (A)

When contamination is detected, the first action is to stop. Stopping immediately prevents any further spread of contamination and protects you from additional exposure while you assess the situation. It also preserves the integrity of the area for containment and decontamination procedures to be carried out safely. Proceeeding with caution can allow contaminants to spread or exposure to continue, while ignoring the detection or delaying reporting delays the containment response and increases risk. After stopping, follow the site’s procedures to secure the area, notify supervision, and start containment and decontamination as instructed.